DS1875 datasheet(13/92 Pages) MAXIM

13 / 92 page

PON Triplexer and SFP Controller

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Pin Description

NAME

FUNCTION

BEN

Burst-Enable Input. Triggers the samples for the APC and quick-trip monitors.

SDA

I2C Serial-Data Input/Output

SCL

I2C Serial-Clock Input

TX-F

Transmit-Fault Output

5, 7, 11, 20,

36, 37, 38

N.C.

No Connection

FETG

FET Gate Output. Signals an external n-channel or p-channel MOSFET to enable/disable the

laser’s current.

TX-D

Transmit-Disable Input. Disables analog outputs.

9, 31, 35

VCC

Power-Supply Input (2.85V to 3.9V)

10, 24, 32, 33

GND

Ground Connection

LOSI

Loss-of-Signal Input. Open-collector buffer for external loss-of-signal input. This input is

accessible in the status register through the I2C interface.

MON5/D0

External Monitor Input 5 or Digital I/O 0. This signal is the open-collector output driver for IN. It

can also be controlled by the MUX0 and OUT0 bits. The voltage level of this pin can be read at

IN0. In analog input mode, the voltage at this pin is digitized by the internal 13-bit analog-to-

digital converter and can be read through the I2C interface. Alarm and warning values can be

assigned to interrupt the processor based on the ADC result.

14, 15, 16

MON6/D1,

MON7/D2,

MON8/D3

External Monitor Inputs 6, 7, and 8 or Digital I/O 1, 2, and 3. In digital mode, these open-collector

outputs are controlled by the OUTx bits, and their voltage levels can be read at the INx bits. In

analog input mode, the voltages at these pins are digitized by the internal 13-bit analog-to-digital

converter and can be read through the I2C interface. Alarm and warning values can be assigned

to interrupt the processor based on the ADC result. D2 is configurable as a quick-trip output for

MON3.

17, 18, 19

MON1,

MON2,

MON4

External Monitor Input 1, 2, and 4. The voltage at these pins is digitized by the internal 13-bit

analog-to-digital converter and can be read through the I2C interface. Alarm and warning values

can be assigned to interrupt the processor based on the ADC result.

21, 22

MON3N,

MON3P

External Monitor Input 3. This is a differential input that is digitized by the internal 13-bit ADC

and can be read through the I2C interface. Alarm and warning values can be assigned to interrupt

the processor based on the ADC result. When used as a single-ended input, connect MON3N to

ground.

DAC1

8-Bit DAC Output. Driven either by I2C interface or temperature-indexed LUT.

M4DAC

8-Bit DAC Output for Generating Analog Voltage. Can be controlled by a LUT indexed by the

voltage applied to MON4.

Converter Feedback. Input to error amplifier. The other input to the error amplifier is an 8-bit DAC.

The DAC can be driven by a temperature-indexed LUT. The output of the error amplifier is the

input of the comparator used to create the PWM signal.

BIAS

Bias-Current Output. This 13-bit current output generates the bias current reference for the MAX3643.

MOD

Modulation Output Voltage. This 8-bit voltage output has eight full-scale ranges from 1.25V to

0.3125V. This pin is connected to the MAX3643’s VMSET input to control the modulation current.

COMP

Compensation for Error Amplifier in PWM Controller

BMD

Back Monitor Diode Input (Feedback Voltage, Transmit Power Monitor)

PWM Output. This is typically the switching node of a PWM converter. In conjunction with FB, a

boost converter, buck converter, or analog 8-bit output can be created.

—

Exposed Pad

DS1875 Datasheet(PDF) 13 Page - Maxim Integrated Products

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